Meeting Abstract

14.3  Friday, Jan. 4  Food, Nuptial Gifts and Vaginae Dentatae: Phenotypic Plasticity and Sexual Conflict in a Gift-Giving Butterfly MOREHOUSE, NI*; BARTOCH, CM; LUNA, EN; ROBERTS, NS; SALEH, NW; University of Pittsburgh nim@pitt.edu

Considerable recent effort has been devoted to understanding the roles of conflict and cooperation in sexual interactions. Gift-giving insects such as crickets and katydids have proven tractable systems for exploring these issues, with recent research emphasizing nuptial gifts as a source of conflict. In the Lepidoptera, males often transfer large nutrient-rich packages called spermatophores internally to females during mating. In contrast to work in other systems, researchers have typically characterized these nuptial gifts as cooperative contributions of mutual benefit to both partners. Male spermatophores provide essential nutrients that increase female lifespan and reproductive output. In turn, males benefit by delaying female remating and thus increasing their paternity share. However, males of many butterfly species, in an attempt to monopolize female reproductive output, package their spermatophores in hard outer shells. Females have, in response, evolved toothed structures in their reproductive tracts called signa, which serve to “chew” their way through the outer spermatophore coating to access the nutrients within. As a preliminary step in understanding the co-evolutionary dynamics in this system, we explored the environmental and genetic determinants of male spermatophore quality and female signa morphology in the gift-giving butterfly Pieris rapae using a split-brood experiment where siblings were reared on artificial diets of varying protein content. We report both high heritability and phenotypic plasticity in both traits. We discuss these results in the context of sexual conflict and co-evolutionary dynamics.